Chapter 15 HAIR LOSS
Hair loss, or alopecia, can be classified in various ways, but the most common classification distinguishes nonscarring from scarring alopecia. The hair loss of scarring alopecia is permanent, whereas that of nonscarring alopecia usually is reversible. When a patient presents with hair loss, it is important to determine whether he or she is experiencing hair shedding, which is significant amounts of hair coming out, or hair thinning, in which more scalp is visible without noticeable amounts of hair falling out.
Cicatricial alopecia results from a condition that damages the scalp and hair follicle. Examination typically reveals plaques of erythema with or without scaling. Syphilis, tuberculosis, acquired immunodeficiency syndrome (AIDS), herpes zoster, discoid lupus erythematosus, sarcoidosis, radiation therapy, and scalp trauma such as burns have been linked to cicatricial alopecia. If the cause of the disorder is not apparent, a punch biopsy of the scalp may be helpful in making the diagnosis.